Is there a preposition in Mando'a that is roughly equivalent to the English "with", "by means of", "via", "using", etc? I picture "ti" as "accompanied by" and "de" as "near", os I don't think they have the meaning I'm looking for. Maybe if one truly doesn't exist, the phrase "teh pirim be" (from the use of) could be used, as in "Ni ku miit'gaana teh pirim be miit'bev" (I wrote from the use of a pen).

I wonder if adol is what I'm searching for, although the English word "through" can mean "by means of" or possibly "so as to make a hole in" as in "going through a wall". I'm imaging the looks on somebodies faces if you were to say "I wrote through (and made a hole inside of) a pencil" instead of "I wrote with a pencil". Shuk'suvare cuyi nuh'la!

That is...hard. My first inclination is that ba'buir's ba isn't related to the one in ba'balut and ba'gedet'ye. I am not sure what the ba in ba'buir could mean though if that's the case. With ba'gedet'ye my guess is that the ba is bah, which is the dative case basically? Which is...expressing that a thing is being given to someone else. It's indicating the noun to which the thing is given. So gedet'ye means "please", and comes from a root that deals with pleading given the word gedetir and also thanks given gedeteyar. Pleading and thanks giving are thus very linked in Mando'a. So you are taking that concept and...stating that you did this thing because of this thing. You are, in a fashion, giving the person their thing that they asked for. That thing they asked for being their plea. So like an example to make this make more sense than I think it is coming off as...

Gedet'ye, ne copaani shig.-a cup of tea is given to the person-Vor entye.Ba'gedet'ye.

Now if I take this and I translate it into EXCEPTIONALLY LITERAL English with respect to ba'gedet'ye I can get something like this

Please, I want tea.-they get the tea-Thank you.I have given your plea to you/To you your plea.

With ba'balut...Again that could possibly be the dative bah? It's the adjectival form of being on patrol. It's not a verb, but a statement that someone is on patrol. It's modifying the person in question. So the idea could be that the person is being given to the patrol. Which I guess makes sense in that...If you are giving someone to a patrol you are putting them on it, yes? It's a thing that needs filling via a person and you have given a person to that job to fill it.

But ba'buir seems odd to think of as being dative? Though I guess the idea could be that as a ba'buir you are the individual that has given a buir to the ad in question. If we are making the argument that this ba is the dative bah. Which sounds a bit weird in English, but it does make a sort of sense. Without a grandparent you do not have your parent. That person just doesn't come into existence. In Mando culture this being either because we didn't give birth to the parent or because we didn't educate the person. So ner ba'buir literally could be "my to me my father".

Completely unhelpful, all I can think of when I try saying ba'balut is the 'brown barbaloots' in The Lorax.I rather like your 'exceptionally literal' translation for ba'getet'ye - it's practical and poetic at once.Ba'buir is a bit tricky, yeah. If I may suggest a wholly usage-based rather than 'grammatical' cause? Try saying buirbuir (essentially a literal translation of 'parent's parent') several times quickly, see what you get. I with my 'Coruscant' accent end up with something like bɛ-bwɛr, or b-bwɛr, allowing for the limitations of the OED symbols in representing a Southland voiced r. Effectively I'm suggesting an analogue to the English 'mama' or Persian 'baba': something you get from small children 'smoothing' words with repetition.

Now I am just thinking of the brown barbaloots wearing buy'ce and standing guard and I don't know how to feel about that.

And oh! The idea that ba'buir is a shortening of buir'buir I like. It does still leave the question of how is ba'vodu aunt or uncle though, yes. However, perhaps, it isn't so much a case of child speak as it is natural shortening of sounds for ease of pronunciation. Similar to how supposedly is often pronounced supposibly in several dialects. So the idea being that the ba is formerally buir in both cases. So buir'buir and buir'vodu. You'd have to make an argument for cousins being considered under the realm of vod in that case though. Or that the terminal u somehow makes it the word cousin. That is the best argument I can currently come up with for how that explanation can work with ba'vodu.

Also I just want to say that if these things are dative constructions I am very, very excited because that's a very interesting form of morphology that you don't see in English. You see it in other languages like Finnish but in English? We use the dative, but not to construct words.

I understand one of the many ways the Roman Catholic church reconciles the fact that Mary had other children (as in 'Jesus, your mother and brothers are looking for you' with their 'perpetual virginity' doctrine is to argue that 'brother' and 'cousin' were used interchangeably. There's no evidence this actually was the case, but I don't see why we can't borrow the idea.

Also, in an adoption-prone society like this, who is actually related to whom would tend to get a bit vague anyway, so you could very well end up with constructions like the New Zealand 'cuzzie bro', used to designate a person who is related to you and of your generation, but you're not sure of the specifics. Aondeug's idea about the -u suffix also bears consideration.Alternatively, ba'vodu isn't 'parent of my cousin', it's 'sibling of my parent', using the form whereby the possessor is placed first, the possession second, and a beten to divide them.